Repeater devices and retimer devices are often employed in digital communication systems to improve signal integrity of a digital signal transmitted through a transmission medium. A repeater device improves signal integrity in a digital communication system by overcoming attenuation and some data dependant jitter of a digital signal that occurs when the digital signal is transmitted through a transmission medium. In operation, the repeater device receives the digital signal on a leg of the transmission medium and regenerates the digital signal along the next leg of the transmission medium. In this regeneration process, the repeater modifies one or more electrical characteristics of the digital signal, such as amplitude, slew rate, and edge to edge timing, without modifying digital information in the digital signal. As a result, the digital signal may be transmitted over a longer distance through the transmission medium while retaining a level of signal integrity.
A retimer device improves signal integrity in a digital communication system by synchronizing data edges of a digital signal to a clock signal. In this way, the retimer device removes all data dependant jitter and all random jitter between the data edges of the digital signal. In some applications, a digital signal includes a number of data streams each of which includes a portion of the digital signal. In these applications, the retimer device reduces jitter between data edges of the data streams and also reduces jitter between data edges across the data streams in the digital signal.
In the process of synchronizing data edges of a digital signal received on a leg of the transmission medium, a retimer device regenerates the digital signal along the next leg of the transmission medium by modifying one or more electrical characteristics of the digital signal without modifying digital information in the digital signal. In this way, the retimer overcomes attenuation of the digital signal that occurs when the digital signal is transmitted through the transmission medium. Because the retimer device performs a synchronization function in addition to performing a regenerating function on a digital signal, the retimer device requires additional circuitry and typically consumes more power in comparison to a repeater device that does not perform such a synchronization function. As a result, an integrated circuit implementation of a retimer device consumes more power and area than an integrated circuit implementation of the repeater device.
Many digital communication systems include packet switches to route data packets along communication paths in a communication network. In these communication paths, the data packets are transmitted through a transmission medium as a digital signal. A packet switch in the digital communication system receives data packets from a leg of a transmission medium along a data path and routes the data packets to a next leg of the transmission medium in the data path. In this process, the packet switch regenerates the digital signal including the data packets and synchronizes the data edges of the digital signal with a clock signal. Typically, the packet switch includes a switch fabric for routing the data packets along the data path in the transmission medium. Generally, the packet switch receives the data packets at an input port of the packet switch, selects one of the output ports of the packet switch based on content of the data packet, and routes the data through the switch fabric to the selected output port. In this way, the switch fabric performs a switching function to switch the data packet from the input port to the selected output port. Because the packet switch performs a switching function in addition to performing a regenerating function and a synchronizing function on the digital signal, the packet switch requires additional circuitry and typically consumes more power in comparison to repeater devices and retimer devices that do not perform such a switching function. As a result, an integrated circuit implementation of the packet switch consumes more power and area than integrated circuit implementations of the repeater devices and retimer devices.